COLUMBUS, Ohio — The state’s new collective bargaining law was defeated Tuesday after an expensive union-backed campaign that pitted firefighters, police officers and teachers against the Republican establishment.

In a political blow to GOP Gov. John Kasich, voters handily rejected the law, which limits the bargaining abilities of 350,000 unionized public workers.

Labor and business interests poured more than $30 million into the nationally watched campaign, and turnout was high for an off-year election.

The law hadn’t taken effect yet. Tuesday’s result means the state’s current union rules will stand, at least until the GOP-controlled Legislature determines its next move. Republican House Speaker William Batchelder predicted last week that the more palatable elements of the collective bargaining bill — such as higher minimum contributions on worker health insurance and pensions — are likely to be revisited.

Earlier this year, thousands of people swarmed the Statehouse in protest when the bill was being heard. The bill still allowed bargaining on wages, working conditions and some equipment but banned strikes, scrapped binding arbitration and dropped promotions based solely on seniority.

Kasich and fellow supporters promoted the law as a means for local governments to save money and keep workers. Their effort was supported by the Ohio Chamber of Commerce, the National Federation of Independent Business-Ohio, and farmers.